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Flashcards in Osteoporosis drugs Deck (17):
1

What are bisphosphonates? How do they work?

they are analogues of pyrophosphate
they bind the surface of hydroxyapatite crystals
they inhibit crystal resprotion: decr. osteoclast function and incr. osteoclast apoptosis (among other things)

2

What are the bisphosponates? (slash what is the suffix)

alendronate, risedronate, ibandronate: oral forms
IV forms: pamidronate and zolendronate. higher compliance for IV forms and may last up to a year for each injection
suffix: DRONATE

3

What are the advantages bisphosphonates

Advantages: long half life; cessation doesn't lead to rapid bone loss because they get integrated into the bone
significant reduction in spinal fractures
can be used in men

4

What are the disadvantages of bisophosphonates?

Disadvantages:
varied effect on nonvertebral site fracture reduction
oral forms may cause esophageal irritation and are contraindicated in pts with severe GERD/Barrett's esophagus
cause muscle aches
oral forms have poor oral absorption, so can be hard to take
small risk of osteonecrosis of the jaw
small risk of atypical fractures

5

What are SERMs? What are associated risks? What is the example drug?

"antiestrogens" with bone augmentation effects
antagonist to breast but agonist to bone
preserves bone mass and prevents vertebral fracture
no added risk of uterine cancer
slight incr. risk of DVT
drug: raloxifene

6

How does calcitonin work? Advantages

non-sex/non-steroid hormone
binds osteoclasts and decreases their activity and number
protects against vertebral fracture

7

Disadvantages of calcitonin

no effect on hip fractures
given as a nasal spray and causes nausea
increased risk of cancer:
not used for osteoporosis

8

PTH in osteoporosis: MOA, what is it?

anabolic agent
daily low dose injections increase bone mass
increases the lifespan of the osteoblasts by reducing apoptosis
basically only used for 2 yrs

9

When do you use PTH for osteoporosis

bone mass decline in a pt on bisphosphonates, estrogen, or SERMS
fracture on bisphosphonates
low turn over osteoporosis
premenopausal women
inability to tolerate other treatments
severe glucocortocoid induced osteoporosis

10

Contraindications for PTH

previous radiation therapy, Paget's disease, history of osteosarcoma (among a few other diseases).
this is based on the fact that PTH casues osteosarcoma in rats

11

What is denosumab?

RANK-ligand inhibitor
given as a subq injection
causes a reduced fracture risk at 3 yrs

12

Denosumab: disadvantages

effect lost if not continued every 6 mo
can cause back and extremity pain, MSK pain, hypercholesterolemia, cystitis
can cause osteonecrosis of the jaw, hypocalcemia, and infections (all rare but serious)

13

metabolism of denosumab

not renally cleared so can be used in pts with reduced renal function

14

What is sclerostatin

influences wnt signaling
inhibition of sclerostatin increases bone mineral density

15

Calcium supplements

may be given as calcium carbonate or calcium citrate
calcium carbonate must be taken with a meal bc needs acidic environment to be dissolved. elderly and pts on H2 blockers may make less acid and calcium carbonate may not be well-absorbed.
calcium citrate is easier to dissolve but causes an incr. risk of kidney stones

16

vitamin D deficiency vs. insufficiency

deficiency (<10 ng/ml) can cause rickets, osteomalacia, and secondary hyperparathyroidism
insufficiency can cause incr. muscle weakness, balance difficulties, incr. osteoporosis rates. may have secondary hyperparathyroidism

17

Osteomalacia and rickets: what is abnormal? What is the most common cause? What are other causes?

total amt of bone is normal but mineralization is inadequate
usually due to nutritional deficiency, but may be caused by calcium chelators, phosphate binders, or intestinal malabsorption
or, phosphate disorders (renal disease with phosphate loss, oncogenic osteomalacia, X-linked hypophosphatemic rickets, renal osteodystrophy)